The invention relates to an apparatus for supplying voltage to a motor vehicle, especially a passenger car, truck or a motorcycle, with a storage cell arrangement that comprises one or more electrochemical storage cells and/or double layer capacitors that are arranged on top of each other.
Electrochemical storage cells and/or double layer capacitors can achieve considerable temperatures in operation, so cooling is necessary. The cooling of the electrochemical storage cells occurs from the outside. If adequate cooling cannot be ensured with sufficient safety, defects can quickly occur that cannot be economically reconciled with the requirements for service life with use in automobiles.
From DE 10 2007 021 293 A1, a drive battery module of an electrical, fuel cell or hybrid vehicle of this general type is known in which one or more profile elements, called “fins,” extend from cooling pipes that have cooling medium flowing through them. What is disadvantageous about this arrangement is the complex structure of the drive battery module, which in the case of a defect requires the complete replacement of the drive battery module.
Therefore, it is the object of the present invention to provide a simply structured voltage supply apparatus for a motor vehicle, especially for the electric motor drive of the motor vehicle, in which adequate cooling with high safety can be ensured by a cooling device.
This and other objects are achieved by a voltage supply apparatus for a motor vehicle, especially a passenger car, a truck or a motorcycle, with a storage cell arrangement that comprises one or more electrochemical storage cells and/or double layer capacitors that are arranged one above the other. The storage cell arrangement can be releasably force fit connected to a heat-conducting cooling device that removes heat supplied from the storage cells and/or double layer capacitors such that at least some of the storage cells and/or double layer capacitors of one respective storage cell group can each be thermally connected to the heat-conducting cooling device.
One advantage of the apparatus according to the invention consists of a simple modular structure in which many common parts can be installed. The apparatus comprises two main components that can be connected to one another with positive locking and can be released from one another, each of which can be designed as common parts. For one thing, the self-contained storage cell arrangement also designated as a module comprises elements between the storage cells and/or double layer capacitors conducting only (passive) heat. For another, the heat-conducting apparatus comprises the elements necessary for cell cooling. The cooling of the storage cells can only occur if the storage cell arrangement and the cooling elements are connected mechanically to one another since only then does the necessary thermal coupling of the two components to one another exist.
The electrochemical storage cells are preferably lithium-based battery cells or nickel-metal hybrid batteries, which are distinguished by high storage capacity with low volume. The storage cells or double layer capacitors each have a circular, prismatic, rectangular or square, oval or flat oval cross section. According to the requirements, in this way storage cell arrangements and/or modules can be formed of several storage cells and/or double layer capacitors that have high packing density. For electrical insulation, their outer circumferential surfaces are designed to be electrically insulating or provided with an electrically insulating layer that preferably conducts heat well.
According to an effective design, the storage cell arrangement includes a storage cell and/or double layer capacitor group. Such a group can comprise two or more storage cells and/or double layer capacitors adjacent to one another. In this case, the storage cells and/or double layer capacitors of a respective storage cell group are connected thermally to each other by at least one heat-conducting profile element, which makes possible a heat transfer between the storage cells and/or double layer capacitors of the storage cell group.
In addition to a good connection of the storage cell arrangement to the heat-conducting cooling device, a uniform temperature distribution between the storage cells and/or double layer capacitors of the storage cell arrangement is achieved. This is achieved by a thermal compensation between adjacent storage cells and/or double layer capacitors of a storage cell and/or double layer capacitor group. The design complication is low here. Because of the uniform temperature distribution between adjacent storage cells and/or double layer capacitors, a high service life is achieved for the apparatus according to the invention.
In order to achieve good heat conduction as well as tolerance compensation between the heat-conducting cooling device and the storage cells and/or the double layer capacitors, an elastic, heat-conducting layer can be provided between these elements. In order to achieve good heat conducting between the storage cells and/or double layer capacitors and the profile elements, they can be glued to each other, whereby preferably a heat-conducting adhesive is used.
In order to achieve not only a thermal compensation between adjacent storage cells and/or double layer capacitors of a storage cell group, but to also achieve the best possible heat dissipation in the direction of the heat-conducting cooling device, according to an advantageous embodiment it is provided that the heat-conducting cooling device is in thermal contact with the at least one profile element. Depending on the design of the at least one profile element, the heat-conducting cooling device can be in contact exclusively with the profile element. Also, the thermal contact can be provided both between the profile element and also one of the storage cells and/or double layer capacitors.
According to another advantageous design, the storage cells and/or double layer capacitors of the storage cell arrangement have a shroud surface as well as a base and cover surface with the respective electrodes connected by the shroud surface, whereby the at least one profile element is in thermal contact at least with the shroud surfaces of the storage cells and/or double layer capacitors of one storage cell group. Because of the large heat transfer surface, uniform temperature distribution is promoted between the storage cells and/or double layer capacitors of a storage cell group.
In order to further improve the heat conduction, the at least one profile element is formed of a material that conducts heat well, especially a metal plate or a (thicker in comparison to this) metal bowl or a filled plastic element.
According to another advantageous embodiment, the at least one profile element has a shape that is adapted to the surface design of the shroud surfaces of the storage cells and/or double layer capacitors of at least one storage cell group. In this way, the heat exchange between adjacent storage cells and/or double layer capacitors, as well as the transfer of heat to the heat-conducting cooling device, is also promoted.
According to another design, the at least one profile element has a wing-shaped cross section, which includes a first and a second contact section. The first contact section is in contact with a shroud surface of a first storage cell and/or of a first double layer capacitor of the storage cell group. The second contact section is in thermal contact with the shroud surface of a second storage cell and/or of a second double layer capacitor of the storage cell group. In this way, the first and the second contact section are connected to each other as one piece in an area between the first and the second storage cell and/or the double layer capacitor. Because of the wing-shaped cross section, it is ensured that the profile element is in contact over a large surface with the storage cells and/or double layer capacitors of at least one storage cell and/or double layer capacitor group. Because of the large area connection produced in this way, uniform temperature distribution is achieved. In addition, heat removal by way of the profile element to the heat-conducting cooling device can also be promoted. Because of the wing-shaped cross section, the assembly of the apparatus according to the invention is also made simpler.
Advantageously, on the free ends of the first and second contact sections of the at least one profile element, a third contact section is connected that is in mechanical and thermal contact with the heat-conducting cooling device. Because of the provision of a third contact section, no special requirements are set for the shape of the heat-conducting cooling device. In particular, the heat-conducting cooling device can have a flat surface that is brought into contact with the respective third contact sections of a number of profile elements.
In an alternative design, one part of the first and the second contact section is in mechanical and thermal contact with the heat-conducting cooling device. This design requires a form-fitting heat-conducting cooling device, by which an outstanding heat transfer from the storage cells and/or the double layer capacitors is ensured.
In particular, the first and/or the second contact section of the at least one profile element comes to rest in a common first and/or in a common second plane in an area turned toward the heat-conducting cooling device. Because of this, a respective flat wall of the heat-conducting device can be brought into mechanical and thermal contact with the first and second contact sections.
In another design, between two storage cell groups that are arranged on top of each other, two profile elements are arranged symmetrically with respect to a plane that runs perpendicular to the direction of extension of the storage cell groups. The two profile elements can be designed as one piece or formed by two separate components. This also ensures simple assembly. If the two profile elements are designed as a single piece, heat exchange between two storage cell and/or double layer capacitor groups disposed on top of one another is also thereby made possible.
In order to ensure high mechanical stability of the apparatus according to the invention, a carrier element is provided between the two profile elements. The carrier element is especially made of plastic and is adapted in its shape. It may be effective if the plastic is also a good heat conductor since then a heat exchange can also occur between two adjacent storage cell and/or double layer capacitor groups.
In another design, the heat-conducting cooling device includes a cooler wall which is provided at the side walls of the storage cell arrangement and has cooling channels that have a heat-removing medium, especially a refrigerant like R 134a, carbon dioxide, R 744, water or air, etc., flowing through it or flowing around it. In this way, heat removal can be ensured continuously in a reliable and adequate manner even during short-term peak loads on the storage cell. The cooling channels can be connected, e.g., in a circuit of an air conditioning system of the motor vehicle.
According to another advantageous design, the cooler wall comprises a flat surface with which it contacts the three contact sections of the at least one profile element. One advantage of this design is that an assembly of the apparatus in an extension direction of the storage cell and/or double layer capacitor groups over each other is possible. Because of this, for example, simple replacement is also possible in the case of a defect in the apparatus without the cooling device having to be replaced.
In an alternative design, the cooler wall has a design that is inverse to that of the storage cell arrangement. In particular, a trough is provided between two storage cells and/or double layer capacitors, whereby in the trough a cooling channel runs. Because of this, the storage cell arrangement can only be mounted in an axial direction of the storage cells and/or double layer capacitors in the heat-conducting cooling device. However, the cooling channels mounted in the troughs can be guided especially close to the storage cells and/or double layer capacitors so that optimum heat removal is possible.
In order to further improve the heat removal, it is also provided that the heat-conducting cooling devices provided on the two opposite sides of the storage cell arrangement are tensioned with respect to each other between at least two storage cells and/or double layer capacitors (and/or storage cell groups and/or double layer capacitor groups) in order to generate a compressive force between the profile elements and the storage cells. At the same time, the heat-conducting cooling devices are also pressed on the storage cells and/or double layer capacitors. Because of this, the heat transfer can be improved.
It is also provided that the heat-conducting cooling device has a heat-conducting element adapted to the design of the storage cell arrangement with which the cooler wall is connected with heat conduction. Because of this, a simple and more cost-effective manufacturing of the apparatus is possible since the heat-conducting element, e.g., is formed from one piece of metal (and without cooling channels). In contrast, the cooler wall can be designed with flat surfaces in which the cooling ducts are arranged.
Another design provides that the storage cell arrangement is stressed in the extension direction of the storage cells and/or double layer capacitor groups arranged on top of each other by at least one tensioning device, especially one made of plastic, with a pre-stress force. The pre-stress force can be created by welding, bolting, or use of a tensioning belt, a clamping pin or tension wire, etc. It is also advantageous if another tensioning device is provided in the axial direction of the storage cells and/or double layer capacitors, which is connected with positive locking or form fitting with the tensioning device named above. Because of this, the previously mentioned tensioning device is held in position so that overall a compact, stable apparatus is provided.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.